How sustainable is bamboo textile?
To begin with, bamboo is a fast growing resource and because of that has turned it into a favorable renewable resource. However, being renewable does not imply that it is sustainable in the processed stage such as with (some) bamboo textile. Since there have been debates about bamboo being a sustainable opportunity for textiles, I decided to look into the textile production process and evaluate, whether bamboo textile is as sustainable as advertised or how it would need to be to be sustainable. To start, I decided to look into the different types of fibre groups used in the textile industry.
There are three basic types of fibre groups:
• Natural fibres
• Regenerated fibres
• Synthetic fibres
“Regenerated and synthetic fibres are collectively known as man-made or manufactured fibres. Natural fibres are, as the name suggests, those which occur in nature, such as wool from sheep or cotton from cotton plants (Kozlowski, 2012a, 2012b). Regenerated fibres are made from natural polymers that are not useable in their original form but can be regenerated (i.e. reformed) to create useful fibres (Woodings, 2001). One of first regenerated fibres was rayon, also referred to as viscose or viscose rayon, regenerated from wood pulp. In contrast, synthetic fibres are made by polymerising smaller molecules into larger ones in an industrial process (McIntyre, 2004), “(Sinclair, R, 2015).
In what category does bamboo textile fall into?
Bamboo in itself is a natural material, it is appreciated for its quick growth and versatile purposes. Bamboo is rich in cellulose, which forms the plant fibres. You can see them in the images below (the dark dotted parts in the culm crosscut). The lighter part is the lignin, the organic substance that is binding the plant fibres.
While bamboo fibres are indeed natural, the process of producing textile from bamboo turns into a man-made production process, which can be divided into two bamboo textile production processes; The mechanical and chemical process.
The mechanical process
In the mechanical process, known as “thermomechanical fibre processing“, fibers are being extracted by firstly splitting the culms or by crushing them. These parts are then being cooked with alkaline phosphatase (a salt, but also natural acting enzyme) to extract the fibres (this step is also known as degumming). Once degummed, the fibres are being washed, dried and spinned for the production of textile.
Because this process involves the use of enzymes for the extraction of the fibers, it is one of the most environmentally friendly methods.
On the left image below you can see the bamboo’s natural very thin fibers, that are difficult to extract by hand. Because they keep their natural “rough” characteristics in the mechanical process, they are less favored by consumers. On the right image you can see two types of fibers. Can you guess, which one is the natural man-made fibre bundle?
The chemical process
The chemical process (regenerated fiber processing) differs largely to the mechanical one. It is used moslty for industrial purposes. It is the process by, which the smooth and soft form of bamboo textile, known as bamboo viscose, is produced (see white bamboo bulk on the image above). In this process all noncellulose constituents of the culm are removed. It could described as any natural surface material that “protects or covers” the fiber (viscose). “Raw cottons, for instance, contain a number of noncellulosic materials that are generally considered to be surface related and may therefore affect fiber quality , ” (Brushwood, 2003).
For the chemical process, a pulping process is used in which the cellulose fibre is seperated from bamboo pulps through chemical applications (see image above). First of all, bamboo fibres are cooked to remove any polymers (kind of like the natural glues) and organic acids. This process helps to losen the fibre structure and to have chemicals penetrate into the fibers more easily. During that process chemicals are added. ” Most common are the Kraft and sulfite pulping processes. Alternatively, alkaline (sodium/anthraquinone) or organosolv (ethanol, or acetic or formic acid) are used and followed by multiple bleaching sequences, ” (Van Dam, 2018). Once the process is completed, bamboo fibres can be filtered and spinned.
The “biofriendly” chemical process
I happened to come across one more “biofriendly” processing method in which Lyocell is produced from bamboo. Lyocell is “a cellulose fiber that is precipitated from an organic solution in which no substitution of the hydroxyl groups takes place and no chemical intermediates are formed, ” (Chen, J., 2015).
During the process of lyocell production (smooth and soft fiber), only one organic compound is used to dessolve the fibers known as N-Methylmorpholine N-oxide (NMMO). The production process then seems to be simliar to the one that produces viscose, with the only difference that waste such as waste water seems to remain in the production system (closed loop production) and therefore does not result into environmental contamination.
As I am reading more about it, I was suprised to see that Lyocell fiber appears to be one of the most sustainable and environmentally friendly once that exist. The only criticism I could find was that the transformation of lyocell fibers into fabric and garments can use many or the same harsh, and even toxic, chemicals and processes used in conventional garments . It can therefore be recommended to purchase it from certified fiber and textile suppliers.
A patent in 2011 regarding the bamboo textile process using pulse shock treatment, high temperature and high pressure cooking process, and microbial treatment as more environmentally friendly approach to process bamboo fiber has been registered;
Is bamboo textile sustainable?
Comming back to the initial question, I would argue that bamboo viscose, used most in the industry, is not sustainable, or in other terms ecologically produced. Many chemicals are being used for the production and it may be unclear, where these and particular waste waters are released to. In addition, these chemicals can also hugely negatively impact the health of manufacturers. Lyocell production, which appears to be less used by the industry, but receives a growing recognition, seems to be promoising in terms of fiber quality, and its closed-loop production process. The traditional, mechanical process, seems to be the most ecological, but less appealing in terms of product quality as the properties of the fibers remain rather natural at this moment. It seems that it is possible to create high quality fibres with the mechanical process, but I could not find sufficient Information.
While I have mixed feelings about the different production processes, I still rate bamboo highly sustainable for textile, due to its fast growth. In comparison to other viscose that is deprived from wood, be it certified or not, I would argue that bamboo fiber provides a sustainable resource in comparison to others such as conventional timber or eucalyptus, which is known for its high rates of water consumption.
Another example is cotton. Gobally cotton covers just 2.4% of the worlds’ cultivated land, but uses less then 6% of the worlds’ pesticides (and 16% of isecticides), more than any other single major crop. On the other hand, bamboo can grow with minimum to no fertilizer and pesticide inputs. Bamboo is a pioneer plant that can grow in margenalized and degraded land, where other crops couldn’t.
For people concerned about deforestation, but not “ecological production”, I would vow for bamboo textile. However, if we were to clear land for the establishment of bamboo plantations I would out-vow bamboo textile!
How does the future for bamboo textile look like?
First of all, I would argue that we should move away from fast-fashion clothing and choose clothing that is made to last. If we buy textile made from wood viscose and throw it away after a single season, we are neglecting the fact that wood takes more then one season to grow. Bamboo on the other hand, which takes around three years to mature, provides a more sustainable opportunity. However, as with bamboo, bamboo fibers have to be produced in such a way that they meet sustainability criterias; sustainable sourced bamboo (minimal pesticide and water control during cultivation) and bamboo sourced from sustainable managed forests, bamboo produced in environmentally/people friendly conditions.
Feedback and/or questions? Feel free to contact me.
References
Bajpai, P. (2018). Biermann’s Handbook of Pulp and Paper: Volume 2: Paper and Board Making. Elsevier.
Chen, J. (2015). Synthetic textile fibers: regenerated cellulose fibers. In Textiles and Fashion (pp. 79-95). Woodhead Publishing.
Brushwood, D. E. (2003). Noncellulosic constituents on raw cotton and their relationship to fiber physical properties. Textile research journal, 73(10), 912-916.
Nayak, L., & Mishra, S. P. (2016). Prospect of bamboo as a renewable textile fiber, historical overview, labeling, controversies and regulation. Fashion and Textiles, 3(1), 2.
van Dam, J. E., Elbersen, H. W., & Montaño, C. M. D. (2018). 1Wageningen Food and Biobased Research, Wageningen, The Netherlands. Perennial Grasses for Bioenergy and Bioproducts: Production, Uses, Sustainability and Markets for Giant Reed, Miscanthus, Switchgrass, Reed Canary Grass and Bamboo, 175.
Sinclair, R. (2015). Understanding Textile Fibres and Their Properties: What is a Textile Fibre?. In Textiles and fashion (pp. 3-27). Woodhead Publishing.
AnnJoest 